Devices and methods for inter-vertebral orthopedic device placement

ABSTRACT

The disclosure relates to devices and methods for implantation of an orthopedic device between skeletal segments using limited surgical dissection. The implanted devices are used to adjust and maintain the spatial relationship(s) of adjacent bones. Depending on the implant design, the motion between the skeletal segments may be increased, limited, modified, or completely immobilized.

REFERENCE TO PRIORITY DOCUMENT

This application claims priority of co-pending U.S. Provisional PatentApplication Ser. No. 60/631,213, filed Nov. 24, 2004 and co-pending U.S.Provisional Patent Application Ser. No. 60/713,235, filed Aug. 31, 2005.Priority of the aforementioned filing dates is hereby claimed, and thedisclosures of the Provisional Patent Applications are herebyincorporated by reference in their entirety.

BACKGROUND

The disclosure relates to devices and methods for implantation of anorthopedic device between skeletal segments using limited surgicaldissection. The implanted devices are used to adjust and maintain thespatial relationship(s) of adjacent bones. Depending on the implantdesign, the motion between the skeletal segments may be increased,limited, modified, or completely immobilized.

Progressive constriction of the central canal within the spinal columnis a predictable consequence of aging. As the spinal canal narrows, thenerve elements that reside within it become progressively more crowded.Eventually, the canal dimensions become sufficiently small so as tosignificantly compress the nerve elements and produce pain, weakness,sensory changes, clumsiness and other manifestation of nervous systemdysfunction.

Constriction of the canal within the lumbar spine is termed lumbarstenosis. This condition is very common in the elderly and causes asignificant proportion of the low back pain, lower extremity pain, lowerextremity weakness, limitation of mobility and the high disability ratesthat afflict this age group. The traditional treatment for thiscondition has been the surgical removal of the bone and ligamentousstructures that constrict the spinal canal. Despite advances in surgicaltechnique, spinal decompression surgery can be an extensive operationwith risks of complication from the actual surgical procedure and thegeneral anesthetic that is required to perform it. Since many of theseelderly patients are in frail health, the risk of developing significantperi-operative medical problems remains high. In addition, thetraditional treatment of surgical resection of spinal structures mayrelieve the neural compression but lead to spinal instability in asubstantial minority of patients. That is, removal of the spinalelements that compress the nerves may cause the spinal elementsthemselves to move in an abnormal fashion relative to one another andproduce pain. Should it develop, instability would require additionaland even more extensive surgery in order to re-establish spinalstability. Because of these and other issues, elderly patients withlumbar stenosis must often choose between living the remaining years insignificant pain or enduring the potential life-threateningcomplications of open spinal decompression surgery.

Recently, lumbar stenosis has been treated by the distraction—instead ofresection—of those tissues that compress the spinal canal. In thisapproach, an implantable device is placed between the spinous processesof the vertebral bodies at the stenotic level in order to limit theextent of bone contact during spinal extension. Since encroachment uponthe nerve elements occurs most commonly and severely in extension, thistreatment strategy produces an effective increase in the size of thespinal canal by limiting the amount of spinal extension. In effect,distraction of the spinous processes changes the local bony anatomy anddecompresses the nerves by placing the distracted spinal segment intoslight flexion.

A number of devices that utilize this strategy have been disclosed. U.S.Pat. No. 6,451,020; 6,695,842; 5,609,634; 5,645,599; 6,451,019;6,761,720; 6,332,882; 6,419,676; 6,514,256; 6,699,246 and otherillustrate various spinous process distractors. Unfortunately, theplacement of each device requires exposure of the spinous processes andthe posterior aspect of the spinal column. Thus, these operations stillpresent a significant risk of pen-operative complications in this frailpatient population.

It would be desirable to design an improved method for the placement ofan orthopedic device between the spinous processes of adjacent spinalsegments. A workable method of percutaneous delivery would reduce thesurgical risks of these procedures and significantly increase theusefulness of these spinous process distractors. This applicationdiscloses a device for the percutaneous placement of inter-spinousprocess implants. The method of use provides a reliable approach thatmaximizes the likelihood of optimal device placement and obviates theneed for open surgery.

SUMMARY

Disclosed are devices and methods that can accurately place anorthopedic device between adjacent spinous processes. The devices andmethods employs a percutaneous approach and constitutes the leastinvasive method of delivery system yet devised. Also disclosed arevarious instruments for implant placement and the implant itself.

Pursuant to a procedure, a patient is placed on his side or in the proneposition. The hips and knees are flexed and the procedure is performedunder x-ray guidance. The level of interest is identifiedradiographically and bone screws are percutaneously inserted into thespinous processes of the upper and lower vertebras of the stenoticlevel. A distractor is placed onto the two screws and a needle is placedthrough the distractor platform and guided into the space between thespinous processes under X-ray guidance. The tip of the needle is guidedinto the exact position where the implant needs to be placed. The needleis marked so that the distance from the needle tip to the center ofrotation of the insertion device (discussed below) can be measured. Theplatform is then immobilized relative to the rest of the distractor andthe spinous processes of the stenotic level are gently distracted. Inorder to gauge the extent of distraction and better standardize theprocedure, a measure of the force of distraction is displayed by thedistraction device. The localizing needle is removed.

A curvilinear device is attached to the platform. The device has a guidearm that rotates about a central point so as to form an arc. Since thedistance from the guide arm's center of rotation to the tip of thelocalizing needle is known, a guide arm of radius equal to that distancewill necessarily form an arc that contains the needle point on itscircumference. A trocar with a knife-like tip is placed through thecentral channel in order to divide tissue before the advancing guidearm. The guide arm is them rotated through the skin and underlyingtissue until the distal end of the guide arm abuts the side of theligament between the spinous processes at the stenotic level. Using thismethod, a curvilinear path is created to the point marked by the needletip in a completely percutaneous manner and without any open surgicaltissue dissection.

The trocar is removed from the guide arm's central canal. The centralcanal is then used to deliver the implant to the desired point between.the spinous processes. Alternatively, a solid guide arm may be used withthe implant attached to the tip.

The placement system described herein provides an easy and reliable wayof placing an orthopedic device within the inter-spinous ligament. Usingthis method, the implant can be placed rapidly, precisely, with a fewsmall skin incisions and the absolute minimum amount of tissuedissection. It permits minimally invasive device placement using onlylocal anesthesia into those afflicted patients who are least able towithstand the stress of open surgical intervention.

In one aspect, there is disclosed a distractor instrument, comprising: afirst distractor member that engages at a distal end to a first skeletalsegment; a second distractor member that engages at a distal to a secondskeletal segment; a distractor device mounted to proximal ends of thefirst and second distractor members; and a distraction actuator attachedto the distractor device, wherein the distraction actuator is actuatedto apply a distraction force to the first and second distractor membersto distract the first and second skeletal segments relative to oneanother.

In another aspect, there is disclosed a distractor instrument,comprising first and second distraction members that each engage arespective skeletal segment, wherein the distraction members can bedistracted to cause distraction of the skeletal segments.

In another aspect, there is disclosed a method of distracting a pair ofspinous processes, comprising using one or more distractor elements toengage the spinous processes to apply a distraction force to the spinousprocesses.

In another aspect, there is disclosed a minimally-invasive surgicalprocedure, comprising localizing a surgical point of interest using alocalizing needle that points to the point of interest; and placing animplant at the point of interest using the localizing needle as a guide.

In another aspect, there is disclosed a minimally-invasive surgicalprocedure, comprising localizing a surgical point of interest using anx-ray to identify the point of interest; relating the point of interestto a delivery apparatus; and delivering an implant to the point ofinterest using an inserter device that pivots about a central axis suchthat the inserter device travels along a curvilinear path that containsthe localized point of interest.

In another aspect, there is disclosed a skeletal implant holder,comprising a hand-operated handle assembly; and a holder assemblyattached to the handle assembly. The holder assembly is configured to beremovably attached to an implant, wherein the handle assembly can beactuated to secure the implant to the holder assembly and to detach theimplant from the holder assembly, and wherein the holder assembly isconfigured to apply a first force to the implant in a first directionand a second force to the implant in a second direction opposite thefirst direction when the handle assembly is actuated.

In another aspect, there is disclosed an implant for implanting betweena pair of skeletal segments, comprising a first segment; at least onewing attached to the first segment, the wing movable between a collapsedconfiguration and an expanded configuration wherein the wing can engagea skeletal segment as an anchor when in the expanded configuration; anda second segment removably attached to the first segment, wherein thesecond segment can be detached from the first segment to disengage thewing from the skeletal segment.

These and other features will become more apparent from the followingdescription and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective, assembled view of a distractor device 100for implanting an orthopedic device between skeletal segments, such asbetween a first vertebral body V1 and a second vertebral body V2.

FIG. 2A shows a perspective view of the device with an insertion devicedetached,

FIG. 2B shows an exploded view of a platform of the device.

FIG. 3 shows a perspective view of the device with the platform removed.

FIG. 4 shows a cross-sectional view of sheaths with screws positionedtherein.

FIG. 5 shows an enlarged, cross-sectional view of the upper region of asheath with a turn screw and a distraction screw a mounted therein.

FIG. 6 shows a perspective view of the device with a localizing needlecoupled thereto.

FIG. 7 shows a perspective view of the device with a locking instrumentcoupled to the platform for locking and unlocking the localizing needle.

FIG. 8 shows a cross-sectional view of the locking instrument attachedto the platform.

FIG. 9 shows a partial exploded view of the platform and shows anexemplary mechanism for effectuating distraction.

FIG. 10 shows a partial cross-sectional view of the platform in anassembled state.

FIG. 11 shows an enlarged cross-sectional view of the platform in theregion of a force pointer that provides a measure of distraction forceprovided to vertebral bodies.

FIG. 12 shows an enlarged view of the pointer and corresponding markingson the platform.

FIG. 13 shows an enlarged view of the locking mechanism and localizingneedle.

FIG. 14 shows the platform with the locking mechanism and localizingneedle coupled thereto.

FIG. 15A shows the device with the platform positioned before it hadbeen moved by a turn screw.

FIG. 15B shows the platform after movement.

FIG. 16 is a perspective view of the device showing how the insertiondevice is pivotably attached to the platform.

FIGS. 17A and 17B show enlarged views of the attachment member of theinsertion device being lowered onto the attachment screw of theplatform.

FIG. 18 shows a cross-sectional view of the attachment member attachedto the attachment screw.

FIG. 19 shows the device including the pivotably mounted insertiondevice attached to a pair of vertebral bodies.

FIGS. 20-22 sequentially illustrate how the insertion device swingstoward the target location where the implant is to be positioned.

FIG. 23 shows the device with a trocar member removed.

FIGS. 24A, 24B, and 24C show an exemplary sizing device for determiningthe appropriate size of an implant.

FIGS. 25 and 26 shows an implant holder device that can be used to holdan implant and install the implant via the internal shaft in theinstaller device.

FIGS. 27A and 27B show the implant with extendable wings in anundeployed (FIG. 27A) and a deployed state (FIG. 27B).

FIG. 28 shows an enlarged view of a portion of the implant coupled tothe holder device.

FIG. 29 shows a cross-sectional view of the implant attached to theholder.

FIG. 30 shows a close-up view of the implant attached to the holder.

FIG. 31 shows the implant locked onto the holder with a handle in alocked position.

FIG. 32 shows a close-up, cross-sectional view of the implant end of theholder.

FIG. 33 shows the holder and attached implant just prior to insertioninto the internal shaft of the curved portion.

FIG. 34 shows the device with the holder and implant in aready-to-deploy state.

FIG. 35 shows the device with the holder and implant in a deployedstate.

FIG. 36 shows a cross-sectional view of the deployed holder and implant.

FIG. 37 shows a close-up view of the implant coupled to the holder.

FIG. 38 shows the implant deployed between the vertebral bodies and theholder removed from the device.

FIG. 39 shows the implant deployed between the vertebral bodies afterthe inserter device has been rotated out of the soft tissue and thedevice and distraction screws have been removed.

FIG. 40 shows how a screw may be removed and the implant disassembled.

FIG. 41 shows another embodiment of a device with a swinging or pivotinginstaller device.

FIG. 42 shows a mounting post in an exploded state.

FIG. 43 shows the mounting post attached to a vertebral body.

FIG. 44 shows a free end of the post a positioned along a line Lparallel to the inter-spinous space.

FIG. 45 shows the insertion device prior to attachment to the post.

FIG. 46 shows the insertion device attached to the post.

FIG. 47 shows an exploded view of an attachment device for attaching theinsertion device to the post.

FIG. 48 shows a cross-sectional view of the attachment device.

FIG. 49 shows a side view of a plunger that couples into the insertiondevice.

FIG. 50 shows a side view of the device with the plunger positionedinside the curved portion of the insertion device.

FIG. 51 shows a perspective view of the insertion device with a taperedend contacting the lateral side of the inter-spinous space.

FIG. 52 shows a perspective view of another embodiment of a distractordevice coupled to vertebral bodies.

FIG. 53 shows another perspective view of the distractor device of FIG.52.

DETAILED DESCRIPTION

Disclosed are methods and devices for implanting a device (such as anorthopedic device) between skeletal segments (such as vertebrae), usinglimited surgical dissection. The implanted devices are used to adjustand maintain the spatial relationship(s) of adjacent bones.

FIG. 1 shows a perspective, assembled view of a distractor device 100for implanting an orthopedic device between skeletal segments, such asbetween a first vertebral body V1 and a second vertebral body V2. Forclarity of illustration, the vertebral bodies are representedschematically and those skilled in the art will appreciate that actualvertebral bodies include anatomical details not shown in FIG. 1.Moreover, although described in the context of being used withvertebrae, it should be appreciated the device 100 and associatedmethods can also be used with other skeletal segments.

The device 100 generally includes a pair of anchors that includeelongate distraction screws 110 a and 110 b (collectively screws 110), aplatform 115, and an insertion device 120 that is pivotably attached tothe platform 115 via an attachment member. A curvilinear trocar 117 isremovably mounted in a hollow shaft of the insertion device 120. Each ofthe distraction screws 110 is attached at a distal end to a respectivevertebral body. In this regard, the distal end of each screw can includea structure for attaching to the vertebral body, such as a threadedshank. The proximal ends of the distraction screws 110 are attached tothe platform 115. The screws 110 are axially positioned within sheathsthat surround the screws and extend downwardly from the platform 115, asdescribed below with reference to FIGS. 3-4.

The insertion device 120 is pivotably attached to the platform 115 suchthat the insertion device 120 can pivot about an axis B. The insertiondevice 120 includes a connecting arm 130 that extends outwardly from theplatform 115, and a curved portion 140 that curves toward the vertebralbodies from an outward tip of arm 130. Arm 130 has a length R thatcorresponds to a radius of curvature of the curved portion 140. Thus,when the insertion device 120 pivots about the axis B, the curved member140 moves along a curved or arced pathway of radius R. The curvedportion 140 can include an internal guide shaft that extends through thecurved portion 140 along the entire length of the curved portion 140.The guide shaft is sized and shaped to slidably receive the trocar 117.The radius of curvature of the curved portion 140 can vary. As describedin detail below, the curved portion 140 acts as a guide for guiding animplant device to a position between the vertebral bodies

FIG. 2A shows a perspective view of the device 100 with the insertiondevice 120 detached. The platform 115 includes a rail 205 that extendsbetween the screws 110 along a direction generally parallel to the axisof the spine. As mentioned, each screw 110 extends upwardly from arespective vertebral body and attaches at a proximal end to the platform115. The screw 110 a attaches to a member 207 that is fixedly attachedto the rail 205. The screw 100 b attaches to a member 209 that isslidably attached to the rail 205. A distraction actuator, such as athumb screw 212, can be actuated (such as rotated) to distract thescrews 110 (and the attached vertebral bodies) relative to one another,as described below.

With reference still to FIG. 2A, a mount 210 is slidably attached to theplatform 115 such that the mount 210 can slide along the length of therail 205, although the position of the mount 210 can be locked relativeto the platform 115, as described below. The mount 210 includes ahollow-shafted attachment screw 215 that can be used to removably attachthe insertion device 120 to the platform 115. The attachment screw 215can also be used to attach a localizing needle (described below) to thedevice 100. FIG. 28 shows an exploded view of the platform 115.

FIG. 3 shows a perspective view of the device 100 with the platform 115removed from the screws 110. As mentioned above, the screws 110 a and110 b are axially positioned within corresponding sheaths 410 a and 410b, respectively. FIG. 4 shows a cross-sectional view of the sheaths 410with the screws 110 positioned therein. For clarity of illustration, theplatform 115 is not shown in FIG. 4. Each sheath 410 has a hollow,internal shaft that is sized to slidably receive a respective screw 110.The internal shaft of the sheath 410 a terminates at an upward end whilethe internal shaft of the sheath 410 b extends entirely through thesheath 410 to form a hole in the upper end of the sheath 410 b.

With reference to FIGS. 3 and 4, a vertical adjustment actuator, such asa turn screw 415, is positioned in the shaft of the sheath 410 b abovethe screw 110 b. The vertical adjustment actuator is actuated to adjustthe vertical position of the platform 115 relative to the vertebralbodies. It should be appreciated that use of terms such as vertical,upward, downward, etc, are with reference to the figures and are notintended to limit actual use.

An exemplary configuration for such vertical adjustment is nowdescribed. An upper region of the turn screw 415 protrudes upwardly outof the platform 1115, as best seen in FIG. 3. FIG. 5 shows an enlarged,cross-sectional view of the upper region of the sheath 410 b with theturn screw 415 and distraction screw 110 b mounted therein. The turnscrew 415 has outer threads that mate with threads on the inner shaft ofthe sheath 410 b. A lower edge of the turn screw 415 abuts an upper edgeof the distraction screw 110 b. When the turn screw 415 is rotated, thelower edge of the screw 415 moves downwardly or upwardly depending onthe direction of rotation. The abutment of the turn screw 415 with thedistraction screw 110 b causes the sheath 410 b (and the attachedplatform 115) to rise or drop relative to distraction screw 110 b andthe vertical bodies when the turn screw 415 is rotated. In this manner,the vertical position of the platform 415 can be adjusted by rotatingthe turn screw 415.

FIG. 6 shows a perspective view of the device 100 with a localizingneedle 610 coupled thereto. As mentioned, the localizing needle 610 canbe inserted through the attachment screw 215. The localizing needle 610has a length such that a distal tip 615 of the needle 610 can bepositioned at or substantially near a target location where an implantis to be placed. The localizing needle 610 includes one or more hatchmarkings 620. Each hatch marking 620 indicates the distance from thedistal tip 615 of the localizing needle 610 to the hatch marking forpurposes of selecting an appropriately-sized insertion device 120 fordelivering an implant to the location identified by the distal tip 615,as described more fully below.

The localizing needle 610 can be locked or unlocked relative to theplatform 115. When unlocked, the position and orientation of thelocalizing needle 610 can be adjusted relative to the platform 115. Forexample, the localizing needle 610 can rotate or pivot to adjust theorientation of the axis of the localizing needle 610. The localizingneedle 610 can also slide relative to the rail 205 of the platform 115by sliding the mount 210 and attachment screw 215 along the rail 205.When locked, the position and orientation of the localizing needle 610relative to the platform 115 is fixed.

FIG. 7 shows a perspective view of the device 100 with a lockinginstrument 705 coupled to the platform 115 for locking and unlocking thelocalizing needle. The locking instrument 705 is configured to tightenonto the attachment screw 215 (FIG. 6) for locking of the localizingneedle 610. When the locking instrument tightens onto the attachmentscrew 215, the localizing needle locks.

This is described in more detail with reference to FIG. 8, which shows across-sectional view of the locking instrument 705 attached to theplatform 115 via threads that mate with threads on the locking screw215. The locking screw 215 has an expandable, spherically-shaped head810 that is positioned within a socket collectively formed by the mount210 and the rail 205. When the locking instrument 705 is not tightenedonto the attachment screw 215, the spherical head 810 is of a size thatpermits the head 810 to rotate within the socket. In addition, the mount210 and attachment screw 215 can slide along the rail 205 when thelocking instrument 705 is un-tightened.

However, when the locking instrument 705 is tightened, a threadedprotrusion 815 causes the head 810 to expand within the socket.Specifically, the head 810 includes an upper half-sphere that contains athreaded protrusion 815, which engages a complimentary threaded borewithin a lower half-sphere. The threads are arranged so that clockwiserotation of the upper half-sphere causes the two half-spheres toseparate from one another. Since the two half-spheres are housed in anenclosed space, clock-wise rotation of the locking instrument causes thehalf-spheres to separate and become frictionally locked relative to therail 205 and the mount 210. In this way, the mount 210 and attachedneedle 610 are locked in position relative to the platform 115.

As mentioned above with reference to FIG. 2A, the device 100 includes adistraction actuator, such as a thumb screw 212, that is actuated (suchas by being rotated) to distract the screws 110 (and the attachedvertebral bodies) relative to one another. FIG. 9 shows a partialexploded view of the platform 115 and shows an exemplary mechanism foreffectuating distraction. The thumb screw 212 attaches to an elongate,threaded lead screw 910 that can be axially inserted into one of therails 205, as represented by the dashed line 915. A biasing member, suchas a spring 920, mounts onto the lead screw 910. A pointer 925 alsomounts onto the lead screw 910 for providing a measure of distractionforce provided to vertebral bodies, as described more fully below. Asmentioned, the member 207 is fixedly mounted to the rails 205, while themember 209 is slidably mounted on the rails 205.

FIG. 10 shows a partial cross-sectional view of the platform 115 in anassembled state. The lead screw 910 engages threads within the rail 205and also engages threads within the slidable member 209. When thethumbscrew 212 is rotated, the attached lead screw 910 also rotates andmoves inward or outward relative to the member 207, which causes theslidable member 209 to move toward or away from the member 207 dependingon the direction of rotation. In this manner, the vertebral bodies,which are attached to the members 207, 209 via the distraction screws110 (FIG. 2A) and the sheaths 410, can be distracted.

FIG. 11 shows an enlarged cross-sectional view of the platform 115 inthe region of the force pointer 910 that provides a measure ofdistraction force provided to vertebral bodies. The spring 920 ismounted on the lead screw 910 in between an internal wall of the memberand a flange 1105 on the lead screw 910. As the lead screw 910 movesalong the direction 1110 in response to rotation of the thumbscrew 212,the spring 920 compresses or expands depending on the direction ofmovement of the lead screw 910. As lead screw 910 turns and members 207209 are moved apart, pointer 925 will move relative to marking 1120 inmanner directly related to the force of distraction. That is, thepointer 925 moves with the lead screw 910 and moves relative to markings1120 wherein the position of the pointer is proportional to the springforce of the spring 920 as the spring expands and contracts. In otherwords, as the distraction screws 110 and attached vertebral bodies aredistracted, the pointer 925 moves relative to the markings 1120 toprovide an indication as to force of distraction. The configuration ofthe hatch markings 1120 can vary. The hatch markings 126 may provide anactual measure of the distraction force in a recognized physical unit orsimply give an arbitrary number, letter, or designation to which theoperator would distract the vertebral bodies. FIG. 12 shows an enlargedview of the pointer 925 and the markings 1120 on the platform.

There is now described a method of use for the device 100. The patientis first placed in a position suitable for the procedure. For example,the patient is placed on his side or in the prone position. The hips andknees are flexed and the procedure is performed under x-ray guidance.The vertebral bodies at the diseased level(s) are identifiedradiographically and the bone screws 110 are percutaneously insertedinto the spinous processes of the upper and lower vertebras. The device100 is then coupled to the distraction screws 110 by sliding the sheaths410 over the distraction screws, as shown in FIG. 3. For clarity ofillustration, certain anatomical details, such as the patient's skin,are not shown in FIG. 3 and in some other figures.

As shown in FIG. 6, the localizing needle 610 is placed through theplatform 115 and percutaneously guided into the inter-spinous space atthe stenotic level. Under X-ray guidance, the needle's distal tip 615 isadvanced until it lies where the operating surgeon wishes to place theimplant. At this stage, the localizing needle 610 is in the unlockedstate so that the surgeon can adjust the position and orientation of theneedle. Once the surgeon has located the distal tip 615 so that it liesat a target location where the operating surgeon wishes to place theimplant, the locking instrument 705 is locked onto the device, as shownin FIG. 7.

As discussed and as shown in FIG. 13, the localizing needle 610 has oneor more hatch markings 620 that indicate the distance from the distaltip 615 to the radial center of rotation of the guide arm. That distancecan be illustrated at each hatch mark on the needle 610, although thedistance is not shown in FIG. 13 for simplicity of illustration. Afterthe needle's distal tip 615 is placed in the desired position, theposition of the needle's hatch marks relative to the top of the lockinginstrument 705 is noted. The distractor device 100 is then moved upwards(or downward) by manipulating the turn screw 415 until the hatch markimmediately above the locking instrument 705 rests immediately adjacentthe top of the instrument 705, as shown in FIG. 14. FIG. 15A shows thedevice with the platform 115 positioned before it had been moved by theturn screw 112 while FIG. 15B shows the platform 115 after movement.Note that the bottom portion of the distractor platform has displacedupward relative to the distraction bone screws.

At this stage of the procedure, the localizing needle 610 is locked inplace with the marking 620 on the needle providing an indication as tothe radius of rotation of the insertion member 120 to be mounted to theplatform 115. With the needle and platform locked, the vertebral bodiesare then distracted. This is accomplished by turning the thumb screw 212which, in turn, moves the lead screw 910 and distracts the member 207relative to the member 209 in the manner described above. As mentioned,the pointer 925 in combination with the markings 925 provide an actualmeasure of the distraction force in a recognized physical unit orprovide an arbitrary number, letter, or designation to which theoperator would distract the vertebral bodies.

At this stage of the procedure, the localizing needle 610 is fixed inplace, the platform 115 is locked in position, and the vertebral bodiesare distracted with the distraction force indicated by the pointer 925.A swing arm is selected with a radius R equivalent to the number, letteror designation of the hatch mark on the localizing needle 610 (the hatchmark 620 at the level of the top of locking instrument). Thus, when theinsertion device 120 is pivoted about the axis B (FIG. 1), the curvedportion 140 moves along a pathway that intersects the target locationdefined by the distal tip of the localizing needle 610.

FIG. 16 is a perspective view of the device showing how the insertiondevice 120 is pivotably attached to the platform 115. The insertiondevice 120 includes an attachment member 1710 (FIGS. 17A and 17B) thatremovably mates with the attachment screw 215 by lowering the attachmentmember 2210 onto the attachment screw 215, as represented by the arrow2110 in FIG. 16.

FIGS. 17A and 17B show enlarged views of the attachment member 1710 ofthe insertion device 120 being lowered onto the attachment screw 215 ofthe platform 115. FIG. 18 shows a cross-sectional view of the attachmentmember 1710 attached to the attachment screw 215. The attachment member1710 includes an attachment screw 1715 that has a threaded bore thatmates with a shank of the attachment screw 215. Once attached, theinsertion device 120 can pivot about the axis B.

At this stage of the procedure, the device 110 including the pivotablymounted insertion device 120 is attached to the pair of vertebralbodies, as shown in FIG. 19. The insertion device 120 is positioned suchthat a distal tip 1910 of the curved portion 140 is positioned above thelevel of the patient's skin. For clarity of illustration, the skin isnot illustrated in FIG. 19.

FIG. 19 shows the insertion device 120 prior to insertion of the trocar117 into the internal shaft of the curved portion 140. FIG. 20 shows thedevice 100 with the trocar 117 positioned within the curved portion 140of the insertion device 120. The trocar has a handle on one end and asharp, knife-like tip 2010 at an opposite end.

FIGS. 20-22 sequentially illustrate how the insertion device 120 swingstoward the target location where the implant is to be positioned. Asmentioned, as the insertion device 120 pivots, the distal end 1910 ofthe curved portion 140 moves along a curvilinear pathway that intersectsthe target location. In FIG. 20, the tocar 117 is slid into the internalshaft of the curved portion 140. The handle of the trocar 117 is thenpushed toward the skin so that the distal end 1910 swings toward theskin along a pathway D. The sharp, knife-like tip of the trocar 117 cutsthrough the skin and soft tissue as the insertion device 120 swingstoward the skin. The trocar 117 and the curved portion 140 are thenforced through the skin and soft tissue as illustrated in FIGS. 21 and22 until the distal tip 1910 of the curved portion 140 abuts the side ofthe spinous processes of the vertebral bodies. Since the swinginginsertion device 120 rotates about the locked platform 115 and arm 130has a radius equivalent to the distance between the center of rotationand the needle tip, the curved portion 140 will necessarily travel alongan arc that intersects the position of the needle tip. As shown in FIG.23, the trocar 117 is then removed leaving the central shaft 2310 of thecurved portion 140 of the insertion device free as a conduit for implantplacement.

In the next step, the appropriate size of the implant is determined,wherein the appropriate size is based upon the size of the space betweenthe two spinous processes. FIGS. 24A, 24B, and 24C show an exemplarysizing device 2410 for determining the appropriate size of an implant.The sizing device 2410 is an elongate rod that is sized to be positionedwithin the shaft 2310 of the curved portion 140. A proximal end of thesizing device 2410 has hatch marks 2414. A distal end 2415 of the sizingdevice has a gradually reducing diameter. As the sizing device 2410 isadvanced further into the curved portion and into the space between thespinous processes, the distal end 2415 of the sizing device 2410 beginsto distract the spinous processes and thereby unload the distractor.

Distraction of the spinous processes can be easily recognized bymovement of pointer 925 (FIG. 12) relative to hatch marks 1120. That is,as the sizing device 2410 is advanced, the pointer 925 will indicatethat less force is borne by the distraction screws 110. Once the sizingdevice 2410 is advanced sufficiently to unload the distraction screws,the implant size is noted on hatch markings 2414 on the sizing device2410. For illustration, this size is shown as “11” in FIG. 24B. Itshould be appreciated that this number may provide an actual measure ofthe implant size in a recognized physical unit or simply give anarbitrary designation by which the implants are labeled. With theimplant size determined, the sizing device 2410 is removed and theappropriate implant is selected.

FIGS. 25 and 26 show an implant holder device 2510 that can be used tohold an implant 2515 and install the implant via the internal shaft inthe curved portion 140 of the install device 120. The holder device 2510includes a handle assembly 2520 having a pair of arms 2522 and 2524. Acurved member 2530 extends outwardly from the handle assembly 2520. Thecurved member 2530 is coupled to a member 2535 and a member 2540, whichare movable relative to one another in response to actuation of thehandles 2522, 2524. The members 2530, 2535, and 2540 collectively form aholder element that holds and secures the implant 2515. The implant 2515has a curvilinear shape and mounts onto the members 2535 and 2540, asshown in FIG. 26 and described below.

FIGS. 27A and 27B show the implant 2515 with extendable wings 2710 in anundeployed (FIG. 27A) and a deployed state (FIG. 27B). The implant 2515has an internal bore 2715. The wings 2710 are formed of foldable arms2720, The implant 2515 also includes ratchets 2730 that are engageableby protrusions 2735. An indentation 2732 is located along a proximaledge of the implant 2515. When the implant 2515 is positioned within thespace between the spinous processes, the implant 2515 is collapsed alongits length, which causes the arms 2720 to fold outward and form thewings 2710. The protrusions 2735 engage the ratchets 2730 to lock theimplant in the deployed state.

The implant 2515 mounts onto the holder 2510 by sliding the members2535, 2540 through the bore 2715 in the implant 2515 such that theimplant 2515 is positioned over the members 2535, 254, as shown in FIG.26. When the implant 2515 is mounted as such, a protrusion 2810 on thedistal edge of the member 2530 engages the indentation 2732 on theproximal edge of the implant 2515, as shown in FIG. 28. The engagementprevents the implant 2515 from rotating when mounted on the members2530, 2540.

FIG. 29 shows a cross-sectional view of the implant attached to theholder. FIG. 30 shows a close-up view of the implant attached to theholder. The members 2535 and 2540 of the holder 2510 are both positionedwithin the central bore 2715 and engage the head of the implant. Ahandle 2910 on the assembly 2520 is actuated to cause the member 2540 tomove back relative to the member 2535 and expand a split ring 3010. Asthe split ring 3010 expands, the ring 3010 wedges against the internalwall of the bore 2715 and thereby lock the implant 2515 onto the implantholder 2510. The locking mechanism at the head of the implant and theprevention of rotation (by engagement of protrusion 2810 and indentation2732 as shown in FIG. 28) effectively immobilize the implant 2515relative to the holder 2510.

FIG. 31 shows the implant 2515 locked onto the holder 2510 with thehandle 2910 in a locked position. FIG. 32 shows a close-up,cross-sectional view of the implant end of the holder 2510. Note thatthe split ring 310 now abuts the inside of the bore 2715 and a conicalhead 3110 of the member 2540 is situated at the distal tip of theimplant 2515.

At this stage of the procedure, the implant 2515 is locked onto theholder 2510 pursuant to the above-described process. The holder 2510 andthe attached implant 2515 can now be inserted into the internal shaft ofthe curved member 140 of the insertion device 120. FIG. 33 shows theholder 2510 and attached implant 2515 just prior to insertion into theinternal shaft 2310 of the curved portion 140. The holder 2510 andattached implant 2515 are slid through the internal shaft 2310 until theimplant protrudes out of the curved portion and is positioned betweenthe spinous processes, as shown in FIG. 34. If needed, a mallet may beused to apply force to surface 3410 of the implant holder 2510 in orderto position the implant between the spinous processes.

The handles 2522 and 2524 of the implant holder 2510 are then actuated,which causes the ends of members 2530 and 2535 to move towards oneanother. The actuation of the handles 2522 and 2524 causes the implantto deform such that the wings 2710 are deployed, as shown in FIG. 35.

FIG. 36 shows a cross-sectional view of the deployed holder and implant.FIG. 37 shows a close-up view of the implant coupled to the holder 2510.The handle 2524 and 2522 are connected to a mechanism that causes themembers 2530 and 2535 to move when the handles are actuated. Themovement causes the implant wings to deploy. Note that the implant'sratchet locking mechanism (the ratchets 2730 and protrusions 2735) isnow locked and keeps the implant in the deployed position. At thisstage, the handle 2910 can be unlocked and the implant holder 2510removed form the central channel of the curved portion 140 of theinstaller device 120. FIG. 38 shows the implant 2515 deployed betweenthe vertebral bodies and the holder removed from the device 100. FIG. 39shows the implant 2515 deployed between the vertebral bodies after theinserter device 120 has been rotated out of the soft tissue and thedevice 100 and distraction screws have been removed.

With reference again to FIG. 27, the implant 2515 includes a screw 2740that secures a first portion of the implant to a second portion of theimplant. When the screw 2740 is in place, the first portion and secondportion are secured to one another. When the screw 2740 is removed, thefirst portion and second portion detach from one another. The implant2515 can advantageously be disassembled by removing the screw 2740. Ifopen surgery is required at a future date, the implant 2515 can bedisassembled and completely removed—making the implantation procedurecompletely reversible. FIG. 40 shows how the screw 2740 may be removedand the implant divided into subunits comprised of a first portion 4010and a second portion 4015. This permits the removal of each subunitwithout removal of the interspinous ligament.

FIG. 41 shows another embodiment of a device with a swinging or pivotinginstaller device 120 having a structure similar to the installer device120 described above. Thus, like reference numerals refer to likestructures. In this embodiment, the installer device 120 mounts at theproximal end of a single mounting post 4110 that attaches at a distalend to the spinous process of a vertebral body V1 or V2.

FIG. 42 shows the mounting post 4110 in an exploded state. The mountingpost 4110 includes a screw 4205 with a shank that screws into the spinalprocess. A two-piece post portion couples to the screw 4205. The postportion has an internal member 4210 positionable inside an externalmember 4215. The internal member 4210 and the external member 4215 arecoupled to one another to form the elongate mounting post 4110, as shownin FIG. 43.

Under X-ray guidance, the screw 4205 of the post 4110 is percutaneouslyattached onto the spinous process through a small skin incision. Theinternal member 4210 of the post 4110 is configured to lock to the screw4205 while the screw 4205 is being driven into bone. In this way,rotation of the outer member 4215 causes advancement of the screw intothe spinous process. The internal member 4210 is then unlocked and theexternal member 4215 is moved in the long axis of the spine until thefree end of the post 4110 rests along a line L parallel to theinter-spinous space, as shown in FIG. 44. The inter-spinous space iseasily identified on X-rays. After this is performed, the internalmember 4215 is locked, which immobilizes the post 4110 relative to thescrew 4205.

After the post-screw is appropriately positioned, the installer device120 is attached onto the proximal end of the post 4110 as shown in FIGS.45 and 46. An attachment member 4125 pivotably attaches the insertionmember 120 to the proximal end of the post 4110. The attachment member4125 is configured to permit the insertion member 120 to pivot about apivot axis B (shown in FIG. 46).

FIG. 47 shows an enlarged, exploded view of the attachment member 4125positioned adjacent an attachment region of the insertion device 120.FIG. 48 shows a perspective, cross-sectional, assembled view of theattachment member 4125. The attachment member 4125 includes a main body4510 having a rounded protrusion 4515 that can be positioned inside theproximal end of the post 4110. A pair of side walls 4520 having inwardlyextending teeth 4525 are positioned on opposite sides of the main body4510. As mentioned, the structural configuration of the attachmentmember 4125 can vary and is not limited to the embodiment describedherein.

With reference to FIG. 47, the attachment member 4125 is attached to thepost 4110 115 by inserting the rounded protrusion 4515 into the proximalend of the post 4110. The two side walls 4520 are positioned on eitherside of the post 4110 such that each tooth 4525 engages a correspondingslot 4530 on the post 4110. In this manner, the attachment member 4125is attached to the post 4110.

With reference to FIGS. 47 and 48, a pivot rod member 4540 ispositionable inside the main body 4510. The pivot rod member 4540includes a pivot rod 4545 that protrude outwardly from opposed sides ofthe main body 4510 when the pivot rod member 540 is positioned insidethe main body 4510. The pivot rod 4545 can be inserted into a pair ofapertures 4555 (FIG. 47) on the insertion device 120 to pivotably couplethe insertion device 120 to the post 4110 via the attachment member4125. The pivot rod 545 defines the pivot axis B (FIG. 46) for pivotingof the insertion device 120.

FIG. 49 shows a side view of an elongate plunger 4810 that slidably fitswithin a guide shaft inside the curved portion 140 of the insertiondevice 120. The plunger 4810 has a tapered tip 4815 on a distal end anda handle 4820 on a proximal end. When the plunger 4810 is fullypositioned in the guide shaft, the handle 4820 protrudes out of one endof the guide shaft and the tapered tip 4815 protrudes out of theopposite end of the guide shaft. FIG. 50 shows a side view of the devicewith the plunger 4810 positioned inside the curved portion 140 of theinsertion device 120.

With the insertion device 110 attached to the post 4110, the handle 4820of the plunger 4810 is then used to push curved portion 140 toward theskin. As the tip 4815 abuts the skin, a small incision is made and thecurved portion is then rotated further until the tapered end 4815contacts the lateral side of the inter-spinous space, as shown in FIG.50 and FIG. 51.

The plunger 4810 is removed and an orthopedic device can then be placedinto the inter-spinous space through the guide shaft comprised of opencurvilinear central bore of the curved portion 140. In this way, adevice can be precisely delivered into the inter-spinous space withminimal tissue dissection. This method will provide a minimally invasiveway of implanting orthopedic devices into this space.

In other embodiments, one or more anchors may be placed into theinter-spinous ligament, lateral to the inter-spinous space, into thepedicles or any other suitable anchor point. The insertion device isthen attached and rotated onto the lateral aspect of the inter-spinalspace. Lastly, the curved portion 140 of the insertion device 120 may bedesigned without a central bore for implant insertion. Instead, theimplant is attached to the tip of the curved portion 140 and deliveredby rotation of the curved portion. Once in place, the implant isdetached from the insertion device 120.

FIGS. 52 and 53 shows another embodiment of a distractor device 5210that is similar to the distractor device 100 described above. In thisembodiment, the distractor device 5210 is attached to a pair ofdistractor members 5315 and 5215 that engage the first and secondvertebral bodies. The distractor member 5215 is an elongate rod having asharpened distal end for penetrating the skin. As shown in FIG. 53, thedistal end does not penetrate the vertebral body but rather engages thevertebral body by abutting a side of the vertebral body.

It should be appreciated that the distractor members can engage thevertebral bodies in various ways. For example, the distractor memberscan be anchors with shanks that actually penetrate into the vertebralbodies. The distractor members can also be clamps that clamp onto thevertebral bodies or can simply by shaped to abut a portion of thevertebral body to purchase onto the vertebral body for distractionpurposes. In addition, one of the distractor members can engage a firstvertebral body in one manner (such as by penetrating the vertebral body)and the other distractor member can engage a vertebral body in anothermanner, such as by simply abutting or clamping onto the vertebral body.Alternately, both distractor members can simply abut a respectivevertebral body without any penetration of the vertebral bodies by thedistractor members.

As shown in FIG. 53, the distractor member 5215 has a structuralconfiguration wherein an anchor 5310 anchors into the respectivevertebral body. The anchor 5310 fits into a sheath 5315 that extendsdownward from a member 5320 on a platform 114. A vertical adjustmentactuator 5325 is located on the member 5320 for adjusting the verticalposition of the platform 114 in the manner described above withreference to the previous embodiment.

Although embodiments of various methods and devices are described hereinin detail with reference to certain versions, it should be appreciatedthat other versions, embodiments, methods of use, and combinationsthereof are also possible. Therefore the spirit and scope of theappended claims should not be limited to the description of theembodiments contained herein.

1.-32. (canceled)
 33. Apparatus for positioning an orthopedic implant ata target location of a skeletal system, the apparatus comprising: theorthopedic implant; and a non-implantable implant holder configured toadvance the orthopedic implant to the target location within theskeletal system, the non-implantable implant holder comprising: anelongated member that extends from a proximal segment to a distalsegment along a curvilinear axis, the elongated member comprising atleast a convex side surface and a concave side surface, the concave sidesurface opposing the convex side surface; handle apparatus extendingoutward from the convex side surface at the proximal segment; a couplerdisposed at the distal segment, the coupler configured to couple withthe orthopedic implant; and a locking feature disposed at the proximalsegment, the locking feature configured to reversibly transition from afirst configuration to a second configuration.
 34. The apparatus ofclaim 33, wherein the locking feature comprises a hand-operated switch,the hand-operated switch operatively connected to the coupler at thedistal segment via a curvilinear linkage that extends through a channelof the elongated member.
 35. The apparatus of claim 33, wherein thelocking feature is configured to: in the first configuration of thelocking feature, enable movement of the orthopedic implant relative tothe non-implantable implant holder; and in the second configuration ofthe locking feature, rigidly affix the orthopedic implant to thecoupler.
 36. The apparatus of claim 35, wherein the coupler isconfigured to, in the second configuration of the locking feature,non-threadedly affix to the orthopedic implant.